Inertial impact switch with normally centered, conductive oscillating contact

ABSTRACT

An inertial impact switch has a housing which comprises to coaxial sections both of which are conductive but are insulated from each other, and a movable contact member normally engaging one generally cylindrical section and spring held out of contact with the other section. The second-mentioned section is the second switch contact element and has a circular flange serving as one mounting terminal; and a second mounting terminal is electrically and coaxially mechanically connected to the firstmentioned section and has an approximately flat surface parallel with the housing axis, so that each of said circular flange and said flat surface of the second mounting terminal can be set on one conductor of a printed circuit on a board to connect the switch in a circuit and firmly mount the switch on the board.

[ 91 [111 3,899,649 Aug. 12, 1975 [57] ABSTRACT An inertial impactswitch has a housing which comprises to coaxial sections both of whichare conductive Bernard M. Jenkins, Chatham, NJ. but are insulated fromeach other, and a movable I contact member normally engaging onegenerally cy- Asslgnee' i f; lindrical section and spring held out ofcontact with ap ewoo the other section. The second-mentioned section isthe June 20,1974 second switch contact element and has a circular flangeserving as one mounting tenninal; and a second [211 App! mountingterminal is electrically and coaxially mechanically connected to thefirst-mentioned section ZOO/61.51; 102/7042 R; 200/6L45 R and has anapproximately flat surface parallel with the H01 35/ 14 housing axis, sothat each of said circular flange and ZOO/61.45, 6l.53, 86 R, said flatsurface of the second mounting terminal can 102/702 R be set on oneconductor of a printed circuit on a board to connect the switch in acircuit and firmly References Cited mount the switch on the board.UNITED STATES PATENTS 2/l96l Kendall ......t....r.. ...m lO2/70.2 R XNORMALLY CENTERED, CONDUCTIVE OSCILLATING CONTACT Inventor:

Filed:

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United States Patent Jenkins INERTIAL IMPACT SWITCH WITH [52] US. CL...

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u U E W V ll Primary A ttorney IIIIIIIIIIIIIIIIIIIIIIIIL ,A

1 INERTIAL IMPACT SWITCH WITH NORMALLY CENTERED, CONDUC'I'IVEOSCILLATING CONTACT BACKGROUND OF THE INVENTION This invention relatesto inertial impact switches of the normally open type wherein a firstcontact element is normally held by a spring in spaced relation to asecond contact element and is brought into momentary closure contacttherewith in response to an impact or shock received by the switch, forexample, as shown by U.S. Pat. Nos. 2,983,800; 2,79l,653 and 3,649,787.

The present invention contemplates a switch wherein the first or movablecontact element is enclosed within and insulated from a housing and thehousing serves as the second contact element, and these contact elementsare connected in electric circuits in different ways, frequently bywires each fixedly attached to one of the contact elements. Such wiresmake it difficult, and in many cases practically impossible to connectthe wires to a printed circuit on a circuit board.

Also, the constructions of most of the prior art switches are toocomplicated and expensive.

SUMMARY OF THE INVENTION One object of the present invention is toprovide a simple and relatively inexpensive inertial impaxt switch, andanother object is to provide a novel and improved construction whicheliminates wires or the like for connecting the switch in a circuit, andwhich can be easily and quickly connected in a printed circuit andfirmly mounted on a circuit board.

The invention contemplates a housing comprising two coaxial sectionsboth of which are conductive but are insulated from each other and oneof which sections preferably is generally cylindrical and serves as asupport for the movable contact element and has a coaxial annularterminal element while the other section constitutes the second contactelement and the other terminal element; and the invention also includesa circular flange on the second-mentioned housing section coaxial withthe housing and serving as a first mounting terminal to engage a part ofa printed circuit, and a second coaxial mounting terminal on thefirst-mentioned housing section having at least one flat side surfacewhich is adapted to set on another part of the printed circuit and holdthe housing against rolling on the circuit board.

In the preferred form of the invention, said second coaxial mountingterminal has a plurality of flat side surfaces similar to a hexagonalnut.

A BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding ofthe invention, reference should be had to the following descriptions andaccompanying drawings in which:

FIG. 1 is a top plan view of an impact switch constructed in accordancewith the invention mounted on a printed circuit board;

FIG. 2 is a sectional view on the plane of the line 2-2 of FIG. 1showing one end of the impact switch in elevation;

FIG. 3 is a similar view on the plane of the line 33 of FIG. I showingthe other end of the impact switch in elevation;

FIG. 4 is a side elevational view of an impact switch mounted on theprinted circuit board which is shown in section on the plane of the line4-4 of FIG. 1;

FIG. 5 is a greatly enlarged central longitudinal sectional view throughthe impact switch, and

FIG. 6 is a horizontal sectional view on the plane of the line 66 ofFIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT Specifically describing theinvention, the reference character A designates the inertial impactswitch which is especially designed for use in connection with a printedcircuit on a circuit board B.

The switch includes a housing which comprises two coaxial sections C andD both of which are electrically conductive but are insulated from eachother and one of which, in the present instance section C serves as asupport for a movable contact element 1 while the other section Dconstitutes a second contact element.

Preferably the section A is cup-shaped and has a bottom wall 2 and acylindrical side wall 3 the outer end of which has a circumferentialoutwardly extending flange 4. The section D has a central dome-shapedportion 5 projecting from a body portion 6. An electrically insulatingdisc 7 is interposed between the body portion 6 and the flange 4 of thesection C, and the body has an inturned edge portion 8 between which andthe flange 4 is interposed another insulating disc 7a. The two housingsections are mechanically connected together in electrically insulatedrelation to each other.

The movable contact element which is shown as comprising a hollow conehaving an outwardlyextending flange 10 at its open end seated on thebottom wall 2 of the housing section C, and a compression spring 11 isinterposed between said flange I0 and the insulating disc 7 so as tonormally hold the cone in approximately coaxial relation to the housing.The apex of the cone extends into the dome-shaped portion 5 of thehousing section D and normally is in spaced relation thereto. Thestrength of the spring II and the normal distance between the apex ofthe conical movable contact element 1 and the portion 5 are such thatwhen the switch is subjected to a sudden impact or shock, the movablecontact element which will engage the dome portion 5 of the housingsection D as indicated by dot and dash lines in FIG. 5 thereby to closea circuit between the two housing sections.

It will be understood by those skilled in the art that inertial impactswitches of this character are commonly used in the art of fusingprojectiles such as bombs, rockets, mortar shells and others; and it isnecessary to provide two terminals on the switch for connecting theswitch in an electrical circuit.

In accordance with the invention, the circular flange 8 coaxial with thehousing provides one mounting terminal, while the other mountingterminal 9 is electrically and mechanically connected to the housingsection C, preferably coaxially therewith and is formed with a surfaceI2 whose plane is approximately parallel to the axis x-x of the housing.Desirably, said surface is approximately flat and is spaced from saidaxis a distance approximately equal to the radius of said flange 8, andin tangential coincidence with the periphery of said flange as shown,for example, in FIGS. 2, 3 and 4. In its preferred form, the terminal 9is polysided like a hexagonal nut, and has a central coaxial hole 13which snugly receives the closed end portion of the housing section C,as best shown in FIGS. 5 and 6. It is desirable but not necessary thatall sides be equidistantly spaced from the housing axis.

This construction is especially adaptable to connecting the switch in aprinted circuit. in FIGS. 1, 2, 3 and 4 are shown portions of a printedcircuit board E on which are printed circuit conductors E and G spacedapart a distance approximately equal to the spacing of the terminals 8and 9 of the switch. The switch is connected in the circuit and at thesame time is mounted on the board E. by placing one terminal 8 on oneconductor F and placing the other terminal 9 on the conductor G, as bestshown in FIG. 4. The flat side of the terminal 9 prevents rolling of thehousing and ensures a stable setting of the impact switch on the board.The terminals are rigidly connected to the conductors by any suitablemeans, for example solder at the points indicated by referencecharacters and 16, respectively.

I claim:

1. An inertial impact switch comprising a housing which includes firstand second coaxial conductive sections electrically insulated from eachother, the first of which serves as a switch contact element, a coaxialmovable contact element normally in conductive engagement with thesecond housing section, said movable contact element being normallyurged by a spring into contact with the second housing section and intospaced relation to the first housing section and adapted to be urged tomomentarily contact with the first housing section in response to animpact received by the switch, said spring having one end directlyengaging said movable contact element and its other end abutting aninsulation disc between said housing sections, said first housingsection having an exterior circular mounting terminal and said secondhousing section having an exterior polysided mounting terminal coaxialwith said circular mounting terminal.

2. An inertial impact switch as defined in claim I wherein said coaxialpolysided mounting terminal is provided with at least one flat surfaceparallel to the axis of the housing.

3. An inertial impact switch as defined in claim 2 wherein said flatsurface is spaced from the housing axis a distance approximately equalto the diameter of said circular mounting terminal in tangentialcoincidence with the periphery of said circular mounting terminal.

4. The inertial impact switch as defined in claim 1 wherein said secondsection is cup-shaped with a bottom wall and a cylindrical side wall,said movable element is conical and has an outwardly projecting flangeat its larger end directly engaging said bottom wall of said secondsection, and said spring is helical and interposed between said flangeon the movable contact element and said insulation disc.

1. An inertial impact switch comprising a housing which includes firstand second coaxial conductive sections electrically insulated from eachother, the first of which serves as a switch contact element, a coaxialmovable contact element normally in conductive engagement with thesecond housing section, said movable contact element being normallyurged by a spring into contact with the second housing section and intospaced relation to the first housing section and adapted to be urged tomomentarily contact with the first housing section in response to animpact received by the switch, said spring having one end directlyengaging said movable contact element and its other end abutting aninsulation disc between said housing sections, said first housingsection having an exterior circular mounting terminal and said secondhousing section having an exterior polysided mounting terminal coaxialwith said circular mounting terminal.
 2. An inertial impact switch asdefined in claim 1 wherein said coaxial polysided mounting terminal isprovided with at least one flat surface parallel to the axis of thehousing.
 3. An inertial impact switch as defined in claim 2 wherein saidflat surface is spaced from the housing axis a distance approximatelyequal to the diameter of said circular mounting terminal in tangentialcoincidence with the periphery of said circular mounting terminal. 4.The inertial impact switch as defined in claim 1 wherein said secondsection is cup-shaped with a bottom wall and a cylindrical side wall,said movable element is conical and has an outwardly projecting flangeat its larger end directly engaging said bottom wall of said secondsection, and said spring is helical and interposed between said flangeon the movable contact element and said insulation disc.